David Schwartzman

David Schwartzman
Howard University | HU · Department of Biology

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63
Publications
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1,170
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Publications

Publications (63)
Article
A transition to a fully global renewable energy infrastructure is potentially possible in no more than a few decades, even using current wind/solar technologies. We demonstrate that at its completion this transition would terminate anthropogenic carbon emissions to the atmosphere derived from energy consumption in roughly 25 years as well as double...
Article
This article reviews Revolutions that Made the Earth. by Tim Lenton, Andrew Watson 433 pp. , Oxford UK, 2013, Price $34.95 (paper) ISBN 978-0-19-967346-9.
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Modelers of the long term carbon cycle in Earth history have previously assumed there is only one stable climatic steady state. Here we investigate the possibility of multiple steady states. We find them in Abiotic World, lacking any biotic influence, resulting from possible variations in planetary albedo in different temperature, atmospheric carbo...
Article
Neo-Darwinian evolution is held to be strongly influenced by mass extinctions triggered by asteroid impacts and volcanic activity. Human civilization and existing biodiversity would not likely survive the former, while mammals and even some dinosaurs (birds) survived the latter. It is important to emphasize that the physical and political economies...
Article
The isotopic composition and concentrations of lead were measured, using mass spectrometric analysis, in blood drawn from 14 young children who lived in Washington, D.C. The isotopic composition of lead in ambient air, which reflects the changing sources of gasoline lead, was also determined for the period of sampling. Blood lead concentrations ran...
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Bill Blackwater's paper is a fine contribution to the critique of Green Capitalism. The uncritical call for an end to economic growth in green agendas tends to isolate greens from the global working class. The uncritical call for an end to economic growth in green agendas tends to isolate greens from the global working class. While information and...
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The degrowth program is highly problematic because of its failure to analyze the qualitative aspects of economic growth and its emphasis on the local economy without recognizing the urgency to address global anthropogenic change from a transnational political perspective. The huge challenge of ending both threats is also an unprecedented opportunit...
Article
It has long been suspected that lichens increase the rate of physical and chemical weathering of rock surfaces, thus playing a role in biogeochemical cycles. However, the relative weathering flux of elements from lichen-colonized rock versus bare rock has been minimally studied; previous attempts to quantify the effect of lichen-cover on weathering...
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We propose consideration of at least two possible evolutionary paths for the emergence of intelligent life with the potential for technical civilization. The first is the path via encephalization of homeothermic animals; the second is the path to swarm intelligence of so-called superorganisms, in particular the social insects. The path to each appe...
Article
Two possible evolutionary paths should be considered for the emergence of intelligent life with the potential for technical civilization, encephalization in warm blooded animals, and swarm intelligence in superorganisms (e.g., termite colonies).
Article
The article presents comments by David Schwartzman in response to the comments made by Petter Næss and Karl Georg Høyer on the former's text. Petter Næss and Karl Georg Høyer's paper is a useful critique of so-called sustainable economic growth under the capitalist mode of production and consumption, in particular the decoupling approach that claim...
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There is now robust evidence for a much warmer climate on the early Earth than now. Both oxygen and silicon isotopes in sedimentary chert and the compelling case for a near constant isotopic oxygen composition of seawater over geologic time support thermophilic surface temperatures until about 1.5-2 billion years ago, aside from a glacial episode i...
Article
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Kleidon (2009) concludes that warm climates impose important constraints on the evolution of large brains relative to body size, confirming our previous hypothesis (Schwartzman and Middendorf 2000). Here we update the case for our hypothesis and present a first approximation estimate of the cooling required for hominin brain size increase using a s...
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Currently, the "practical struggle" opening up a way to a socialist future is forced to confront the looming threat of ecocatastrophe stemming from climate change. The catastrophe threat is no longer a potential contingent outcome in some indefinite future of the unsustainable mode of production and consumption of global capita reproduction but ins...
Conference Paper
Background/Question/Methods The case for a hot early climate now grows more robust, as evidence mounts from a variety of sources including isotope geology and molecular phylogeny. The Earth's climate evolved from a hothouse starting some 4 billion years ago, with thermophilic conditions, only cooling to a near icehouse state starting about a bill...
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Apparent cyanobacterial emergence at about 2.8 Gya coincides with the negative excursion in the organic carbon isotope record, which is the first strong evidence for the presence of atmospheric methane. The existence of weathering feedbacks in the carbonate-silicate cycle suggests that atmospheric and oceanic CO2 concentrations would have been high...
Article
The continuing use of Georgescu-Roegen's theory of entropy by neo-Malthusians as foundational support for their views comes as no surprise. Lately, those warning of a Hubbert Peak apocalypse have commonly drawn from the same conceptual well. But unfortunately even Marxist scholars still do the same. Paul Burkett's recent paper supporting Georgescu-...
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The timing of emergence of major organismal groups is consistent with the climatic temperature being equal to their upper temperature limit of growth (T_{max}), implying a temperature constraint on the evolution of each group, with the climatic temperature inferred from the oxygen isotope record of marine cherts. Support for this constraint comes f...
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We revisit the case for the hyperthermophilic scenario for the origin of life and the last common ancestor. Evidence includes studies of phylogenetic trees, rRNA, G and C content, hyperthermophilic proteins, correlations between maximal temperature tolerances and genetic distances, saline stabilization of DNA/RNA, and the inferred climatic temperat...
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We review the thermal history of the Universe. We obtain a new estimate for the thermal history of the Earth over the past four billion years using a biological thermometer based on (1) a rough estimate of the absolute time calibration of the genetic distances in the 16S rRNA-based tree of terrestrial life and (2) the maximum growth temperatures of...
Article
The idea that living things and the atmosphere, oceans, and soils comprise an interactive, self-regulating system-the Gaia concept-was first proposed nearly thirty years ago. Since then researchers have been seeking new connections between life and the global environment. David Schwartzman contributes to that search by examining how the Earth's bio...
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The long-term cooling history of the Earth's biosphere implies a temperature constraint on the timing of major events in biologic evolution, e.g., emergence of cyanobacteria, eucaryotes and Metazoa apparently occurred at times when temperatures were near their upper growth limits. Could biospheric cooling also have been a necessary condition for th...
Article
A characteristic hallmark of life is its homochirality: all biomolecules are usually of one hand, e.g. on Earth life uses only L-amino acids for protein synthesis and not their D mirror images. It is therefore suggested that a search for extra-terrestrial life can be approached as a Search for Extra-Terrestrial Homochirality (SETH). A novel miniatu...
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Full-text available
A global economy powered by non-solar energy sources is limited by global warming, finite reserves and concomitant insults to the earth's biosphere, including our own species. Some of these impacts, such as loss of biodiversity, will be irreversible. Without constraints on the reproduction of capital, the global driver of the contemporary environme...
Chapter
One of the most characteristic features of life is its homochirality: all biomolecules are of one hand, e.g. terrestrial life is based on all-L amino acids and all-D sugars. Non-living systems are normally racemic, so homochirality (or at least an enantiomeric excess) is almost certainly a sign of life or pre-biotic chemistry. So a search for extra...
Article
Experiments with Methanothermus fervidus (strain V245) were performed. Microbial colonization by M. fervidus was evident on an anorthite chip from the normal media, with a suggestion of etching, revealed after cleaning the surface with alcohol and hydrogen peroxide. No evidence of colonization was seen on anorthite in reduced media or on forsterite...
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Recently scientists have proposed that some, if not all, ancient glacial deposits are really impact deposits. The proposition that glaciation may not have occurred before the Cenozoic raises for reconsideration the surface temperature history of earth. The authors examine the information available and propose the following scenario. Just before the...
Article
Schwartzman contends that lichens and other microbes may significantly contribute to chemical denudation of exposed rock by their combined physical and chemical activity. Lichens do not generate a thick soil but they do stabilize already existing soil (cryptogamic). Studies on chemical denudation in soil-free alpine terrains may contribute to a bet...
Article
Schwartzman contends that lichens and other microbes may significantly contribute to chemical denudation of exposed rock by their combined physical and chemical activity. Lichens do not generate a thick soil but they do stabilize already existing soil (cryptogamic). Studies on chemical denudation in soil-free alpine terrains may contribute to a bet...
Article
NASA The authors present two scenarios for the temperature history of Earth. One scenario is conventional, the other relies on a warmer history. Both scenarios include surface cooling determined by the evolution of the biosphere and are similar until the Proterozoic period. The warmer scenario requires a higher plant/lichen terrestrial biota to inc...
Article
Assuming steady state of carbon dioxide levels in a “pressure-cooker” atmosphere/ocean system (10–20 bars, near 100°C) produced by a land weathering sink and volcanic source (BLAG model), an abiotic Earth model for 3.8 Ga requires present biotic enhancements of weathering to be on the order of 100 or greater, consistent with the limit inferred from...
Article
AN important question in the Earth sciences is the role of the biota in the chemical weathering of silicate rocks, which affects atmospheric CO2 and therefore climate1-10. No comprehensive study of biotic influences, however, has quantitatively examined the climatic consequences were weathering to take place under completely abiotic conditions. Her...
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The search for extraterrestrial intelligence is examined, including studies to listen for electromagnetic signals from other civilizations and to estimate the possible number of technological civilizations in the universe. The Green Bank equation is presented, discussing its use in estimating the civilizations capable of interplanetary communicatio...
Article
The paper reviews the history of alternating optimistic and pessimistic expectations of searches for extraterrestrial radio communications. It is pointed out that a proper consideration of such searches should distinguish between those anticipating beacons from advanced civilizations and those anticipating leakage radiation from emergent civilizati...
Article
The potential use of lichens as quantitative monitors of airborne heavy metal pollution has been demonstrated by measurements of Po210, Pb, Cd, Zn, and V levels in sequential growth of the foliose lichen Pseudoparmelia baltimorensis from three localities in the greater Washington, D.C. area. Samples were dated using the growth rate measured by Lawr...
Article
The absence of extraterrestrials on Earth in spite of the probable existence of a “Galactie Club” is a result of our nearly unique position on the verge of becoming a memeber. This supports the view that we are under surveillance by extraterrestrial intelligence, and reduces the likelihood of contact by radiotelescopes.
Article
Diffusion of argon from two bronzite pyroxenes from the Ultramafic Zone of the Stillwater complex, Montana, has been measured by both a stepwise heating Ar release process and long term isothermal heating. Both pyroxenes contained excess Ar40. This amounted to at least 88% of the total radiogenic Ar40 in the minerals. The Ar release occurred by at...
Article
BROWN et al.1 have treated the problem of the history of the argon degassing of the Earth, and claim to demonstrate that the 40Ar/36Ar ratio in the mantle has increased from ~133, 770 Myr ago, to a value that ``is at present not greater than the atmospheric ratio (295.5) and is probably a little lower''. Their Table 1 and Fig. 1 show the results of...
Article
The degassing of radiogenic Ar40 is defined as coherent if only the Ar40 associated with parent K is degassed as K is transferred from the mantle to crust. Coherency predicts, for a 4.55 b.y. Earth, a sialic crust with 2.50 per cent K, using only the Ar content of the atmosphere and present crust (from a Hurley and Rand, 1969, age distribution). Th...
Article
THERE have been many attempts to model Ar degassing of the Earth. In one category1–6 models are implicitly coherent in regard to K and Ar; 40Ar which has been accumulating with parent K in the mantle is degassed when K enters the crust. I have discussed in detail the implications of such a model to the origin of the sialic crust elsewhere (refs 7 a...
Chapter
Full-text available
We argue that the biosphere has evolved deterministically as a selforganized system, given the initial conditions of the Sun-Earth system. With temperature as a critical constraint, biogenesis and the overall patterns of biotic evolution were the highly probable outcomes of this deterministic process. Emergence of life and its major evolutionary in...
Article
The chapter discusses the interrelated aspects of biomonitoring using chemical analysis of lichens. Many unique aspects of study objectives, study design (including design tasks, considerations, and sampling schemes), sample collection, sample preparation, and sample analysis that are required for a successful biomonitoring program using chemical a...
Article
1. Thermal Determinism and the Narrow Roads of Prebiotic Chemistry Modern cosmology gives us the largest context within which to understand the emergence of life in the universe. Within this context, the transition from molecular to biological evolution is the most recent in a series of transitions that can be easily described as the result of decr...
Article
It has been observed that deep-sea basalt glasses are depleted in Ar-40 rad. and He-4 relative to the concentrations predicted by Schwartzman's coherent model (1973). The depletion mechanism may be the partitioning of rare gases between the magma and a vesiculating gas phase. Data have indicated a partial equilibrium line on an Ar-40 vs Ar-36 total...